LONDON, Feb. 28 -- British stargazers were poised to catch a rare "planetary parade" as all seven of Earth's neighbours form a spectacular lineup this week, before it fades away until 2040.

Mars, Jupiter, Uranus, Venus, Neptune, Mercury and Saturn will be visible together in the UK during a brief window between sunset and around 1830 GMT.

Even though the planets are separated by huge distances in space and orbit the Sun at different speeds, there are moments when they appear to align from Earth's perspective.

Mercury has now joined the six other planets already in formation, and experts say the best chance of seeing all seven in the UK is from Tuesday to today.

The heavenly show has already been dazzling spectators around the world, f...